Multithreading in programming refers to the capability of a CPU or a single core within a multi-core processor to provide multiple threads of execution concurrently. This technique enables programs to perform multiple tasks simultaneously, improving efficiency and response times. For example, a program can handle user interface interactions, while simultaneously processing data in the background. Multithreading is particularly valuable in applications that require high performance and responsiveness, allowing developers to create smoother experiences without blocking or slowing down the application.